...is magical.

When he first gets it he wields it like a butterfly knife!

Later on, he messes with it just like a folding machete!

Then Daud has it and it is a switchblade!

Each scenario the blade is longer than the handle.

Piero does amazing work.

Well it folds into itself. Presumably by collapsing downwards several times. What puzzles me is that it seems seamless when you first get it.

It cannot be a very good sword from any realistic technological standpoint. Any solidly made sword would be much better. I wish I could have used the Officers Sword instead of some flimsy feeling foldout blade. Not a fan of the sword. Love everything else though.

Blade design concept artwork:

http://www.creativeuncut.com/gallery-23/dh-corvo-sword.html

I love it when Corvo flips the sword to a different stance when entering stealth mode

lol, I love the description "mechanism"! So, we have designed this gimmicky sword, noone really knows how it is supposed to work or not fall apart, but due to these two "mechanisms" it's a masterpiece of engineering!
Well, I'm not a big fan of the folding blade - although I have to adimit it looks pretty neat - as there is no reason for Corvo to have such an unreliable, instable gadget. The blade isn't even very long, so he could easily carry it around (and even conceal it, if that was ever necessary) in a sheath.

On the other hand, the sword flip while changing stances, now that is something I love too. Oof actually claimed the move was impossible to execute, so I had a closer look at it and it DOES look a bit goofy. Still I think it could be done (http://www.gamesas.com/topic/1417228-mention-one-little-detail-in-dishonored-do-you-like/page__view__findpost__p__21661928 andhttp://www.gamesas.com/topic/1417228-mention-one-little-detail-in-dishonored-do-you-like/page__view__findpost__p__21662318 for refence).

Even, if it isn't that long, carrying it around just like a normal sword, beside your leg, it could caught onto something or when turning or walking besides a wall, it could hit the wall/floor/other object, which can make a sound, if we are looking from a realistic point of view.

(When you hit your sword for example on a wall it will make a sound, which can alert guards.